The present invention relates to an electrical connector. More specifically, the present invention relates to an electrical connector attached to a circuit board.
A conventional electrical connector (a connector) is disclosed in Patent Reference. The connector for a circuit board in Patent Reference includes a housing (an insulating main body) formed with a recess portion for receiving a mating connector opening in an upper direction and a plurality of terminals held in the housing.
The housing includes a convex portion situated in a central portion of the recess portion of the housing. The convex portion has an island shape and protrudes in the upper direction from a bottom wall portion as a wall portion. The recess portion surrounds the convex portion circularly upon being viewed from the upper direction. A plurality of the terminals is disposed in both ends of the convex portion along a sidewall of the housing to be symmetrical relative to the convex portion.    Patent Reference: Japanese Utility Model Publication No. 3108400
The terminal has a lateral S-shape and is made by punching a metal plate while a plate surface thereof is maintained. The terminal includes a contacting arm portion extending along the wall portion of the convex portion in the recess portion, and a holding arm. The holding arm has an upside-down U-shape including two leg portions extending over an upper end of the sidewall of the housing then to a lower direction. The terminal further includes a combining portion for combining a lower end of the contacting arm portion and a lower end of one of the leg portions, and a connecting portion (a soldered portion). The connecting portion extends outside from a lower end of the other of the leg portions. The connecting portion of the connector in Patent Reference is soldered to a corresponding circuit portion of the circuit board.
The two leg portions of the holding arm extending in the lower direction sandwiching the sidewall. The two leg portions include protrusions protruding toward an inner surface and an outer surface of the sidewall, respectively. The sidewall is inserted between the two leg portions of the holding arm, so that the terminal is attached to the housing from the upper direction. The holding arm sandwiches the sidewall as well as the protrusion bites into the surface of the sidewall.
To downsize the connector for the circuit board is highly demanded. Thus, for example, a thickness of the sidewall of the housing is reduced. In the connector disclosed in Patent Reference described above, the sidewall is sandwiched with the holding arm. The sidewall holds the holding arm by being pressed both of the outer surface and the inner surface thereof with the protrusions provided on the holding arm. Therefore, in order to obtain enough strength for the sidewall, it is necessary to make the sidewall thick.
The holding arm is necessary to be strong enough against a reaction force from the sidewall generated by pressing the sidewall with the protrusion, adding to forming the protrusion thereon. Accordingly, it is necessary to be the holding arm wider. Consequently, since the sidewall of the housing becomes thicker and the holding arm of the terminal becomes wider, the connector grows in size.
Further, when the connecting portion of the terminal is soldered to the corresponding circuit portion of the circuit board, an external force is transmitted to the leg portion of the holding arm extending along the outer surface of the sidewall as the connector receives the external force inadvertently by twisting the mating connector and so on. As a result, the external force is transmitted to a soldered portion, where the connecting portion and the corresponding circuit portion are soldered. Consequently, an electric connection may be poor at the soldered portion.
Furthermore, when the terminal is attached to the housing, the surface of the sidewall can be scraped with the protrusion of the leg portion as the sidewall is inserted between the leg portions of the holding arm of the terminal. As a result, scraped wastes can be generated by scraping and the scraped wastes can remain on the sidewall. Therefore, upon using the connector, an electrical conduction becomes poor at the corresponding circuit portion since the scraped wastes can fall and adhere on the corresponding circuit portion on the circuit board.
In view of the problems described above, an object of the present invention is to provide an electrical connector for a circuit board capable of reducing a size thereof as well as maintaining electrical conduction well at a soldered portion and a good connecting state at a corresponding circuit portion.
Further objects and advantages of the invention will be apparent from the following description of the invention.